It can shrink colormaps and change images to use the
Web-safe palette (or any colormap you choose).

Optimize your animations! This stores only the changed
portion of each frame, and can radically shrink your GIFs. You can also use
transparency to make them even smaller. Gifsicle’s optimizer is pretty
powerful, and usually reduces animations to within a couple bytes of the
best commercial optimizers.

Unoptimizing animations, which makes them easier to edit.

A dumb name.

Two other programs are included with gifsicle: gifview is a
lightweight animated-GIF viewer which can show animations as slideshows or
in real time, and gifdiff compares two GIFs for identical visual
appearance.

Gifsicle questions

Let the person who isn’t actually buying anything but is
rather downloading something for free, beware.

Q: How do you pronounce “gifsicle”?
A: “Yo’ mama.”

Q: What about patents?
A: The GIF image format had some patent problems in the past,
but according to the Free Software
Foundation, “The Software Freedom Law Center says that after 1 October
2006, there will be no significant patent claims interfering with
employment of the GIF format.” [reference]

Other GIF tools

Whirlgif (an older version) merges
single GIFs into animations, but cannot extract frames, edit animations, or
use animations as input files. It either uses local color tables, or it
changes input colors by only using colors from the first GIF frame. It also
cannot handle complicated input transparency or more than 256 colors total.
Gifsicle now uses its adaptive tree method for LZW encoding (thanks!) which
makes it basically as fast as Whirlgif.

GIFMerge is based on
an earlier program called txtmerge. Like Whirlgif, it cannot extract frames
or edit animations. It also cannot optimize animations. Resulting
animations always have local color tables. Doesn’t deal with input
transparency.

There’s at least one GIF optimizer available via the Web. Submit a
GIF URL to OptiView, and it spits
out several impressively optimized versions for you to select from.
As of mid-1998, gifsicle -O2 usually did about as well as GIF Wizard,
OptiView’s predecessor.

It is vastly better than GIFMerge and Whirlgif, in every way I
could think of. Not least importantly, it reduced the GIF animations on my
web site from 19MB total down to 11MB, which suddenly made my site much
easier to navigate.

Don’t be so hard on poor Anne, whoever she is; Gifsicle
isn’t such a bad name (at least it’s
memorable.)”

Testimonials Européens

Testimonialae Africanae

Etienne Posthumus’s “rough” translation: “Well old
boy. I haven’t downloaded it yet, but it looks hot-shit to me without a
doubt.”An independent translation: “Sure bro. I
still haven’t downloaded the thing yet, but it looks to me without a doubt
like wet shit.”